Method of treating electric-furnace products.



. E i l ALDUS' c. rneems AND enonen N. Jnrr'son, or woncns'rnn, MAssAcnusn'r'rs:

METHOD OF TREATING ELECTRIC-FURNACE PRODUCTS.

No Drawing.

To all whom it may concern:

and GEORG N. JnPPsoN, citizens of the United States, residing at Worcester, in the county of \Vorcester and State of Massachusetts, have invented certainnew and useful Improvements in Methods of ,Treating Electric-Furnace Products, of which the following is a specification.

This invention relates to the treatment of certain refractory products of electric furnace operations, these products being adapted for use, after bonding, as abrasives, refractoriesor the like, the object of the inventlon being the provision of a method of enhancing 'or'improving the bonding qualities of the grains, as well as their adhesive qualities in the preparation of abrasive papers, cloths or thelike.

The method is applicable to a variety of;

electric furnace products, among which may be mentioned silicid of carbon, and the aluminous ,products resulting from the fusion of commercial bauxite, alumina or aluminous silicates. We have found that by treating such products with an alkaline reagent under "suitable conditions as hereinafter described, we are enabled to improve their bonding qualities and thereby to increase very considerably the strength of the bonded articles, or in case of-abrasive paper or cloth, the adhesion of the grains.

We may proceed as folloWs:. The electric furnace product, as for example the pig or mass resulting from the fusion of calcined bauxite or other aluminous material, is crushed, preferably but not necessarily to such size or sizes as may be suited for use or for thesubsequent manufacture of abrasivewe may employ an aqueous solutioncontaining caustic soda or sodium carbonate or preferably a mixture of caustic soda and sodium carbonate", a suitable solution containing 15 pounds ofcaustic soda and 12 pounds of sodium carbonate dissolved in 50 pounds of water. Satisfactory results are obtained bysubjecting the aluminous ma terial to this solution, maintainedat or near its boiling point, fora period of from one to two hours. As a modified method of Specification of Letters Patent.

Patented Dec. as, race.

.Applieation filed April 23,1909. Serial No..491,728.

\ treatment, thealuminous 'material may be Be it known that we, ALnUs C. HIGGINS" subjected in presence of a small proportion of dry sodium carbonate or sodium hydroxid, or a' mixture of these compounds, to a temperature above the melting-point'of the compound or mixture employed. The alkali in this case acts energetically upon anyunconverted or unfused alumina which may be present, but under pr oper conditions is without substantial action upon the alumina which has undergone fusion inthe electric furnace. The amount of alkali employed in this case is preferably apnroxi mately proportionate to the percentage of fluxible impurities inthe material to be treated. The material treated in accord ance with either of the above methods may then be subjected to such further operations as may be required, as washing with water or dilute acid, grinding or crushing, grading, etc, and may then be molded and fired in the usual manner, using any of the customary vitrified, pottery or ceramic bonds, as for example a mixture of clay and feldspar; ora suitably graded material may be directly utilized, or may be applied to the.

production of articles not requiring firing, as for instance abrasive papers and the like; for this latter use it is found to present particular advantages, the glue or binder adhering to the grain with great tenacity.

The product treated as above is uniform in character, and implements or articles prepared therefrom by bonding, either with or without firing, are found to possess increased strength and durability.

As regards the nature 'of the effect of the alkaline reagent, it may be suggested, without thereby limiting the invention, that electric furnace products of the character indicated usuallyi containa small proportion of reduced or segregated impurities,

which" consist of minute irregularly disseininated particles of reduced-metals, al-

loys, carbids or the like, or of Segre-- gated metallic 'oxids. These are probably attacked by the reagents used, leaving small cavities -which receive and retain,

the 5 glue .or other compound. In addition, there is quite probably an action upon the-surface of the grain, which is thereby verted alumina, thereby not only improving the holding quality of theproduct but also improving the character of the grain. Whatever maybe the eflect of the treatment upon the grain, the result is a definite and marked increase in the capillary action of the grains. This may be illustrated by placin the dry products, treated and untreate in open-ended glass tubes, the lower ends of which are immersed in water. It is found that the water rises in the tubes containing the treated material to a much greater height and'at a much more rapid rate than in those containin the untreated material. In practice it is lound that this test affords a satisfactory indication as to the bonding qualities of the grains.

Ve claim: p 1. The method of-improving the bonding qualities of abrasive and refractory materials produced in the electric furnace, which consists in subjecting such materials suitably subdivided, to the action of an alkaline reagent.

2. The method of improving the bonding ALDUS c. HIGGINS.

GEORGE N. JEPPSON.

Witnesses:

ALFRED S. MERRIFIELD, HENRY DUCKWORTH. 

